Incinerator unit



Dec. 13, 1960 v. w. UHL ETAL INCINERATOR UNIT 3 Sheets-Sheet 1 1 l;;fl re an Filed Jan. 17, 1958 INVENTOR S VINCENT W. UHL

Y VALENTINE STURMAN W NEE ATTYS,

Dec. 13, 1960 v. w. UHL ETAL INCINERATOR UNIT 3 Sheets-Sheet 2 Filed Jan. 17, 1958 FIGS.

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Dec. 13, 1960 v. w. UHL ETAL INCINERATOR UNIT 3 Sheets-Sheet 3 Filed Jan. 17, 1958 E N N INVENTORS, VINCENT W. UHL VALENTINE STURMAN ATTYS.

United States Patent 1N CINERATOR UNIT Vincent W. Uhl, Villanova, and Valentine Sturman, Quaker-town, Pa., assignors to Bethlehem Foundry & Machine Company, Bethlehem, Pa., a corporation of The present invention relates to an incinerator for wet material, and more particularly to an incinerator having a dryer section which affords continuous drying and incineration of the material.

One standard practice for drying wet material consists of passing the wet material first through a drying kiln and then transferring the dried material from the drying kiln to a second kiln in which the material is incinerated. Another method consists of employing a multiple hearth, Herreshofi type of furnace wherein the material is passed down step-by-step through a plurality of hearths under the action of a central rotary impeller common to all of the hearths and having pushers or the like operating upon the material on each hearth to cause the downward travel thereof. Although these procedures are satisfactory for incinerating the material, they are much more complicated and require more costly equipment than the apparatus of the present invention.

With the foregoing in mind, the present invention provides a novel apparatus for drying and incinerating wet material embodying a unitary rotary kiln having means to effect drying of the material at one end, means to effect combustion of the material at the other end, and means for continuously advancing the material from the one end to the other end.

More particularly, the present invention provides means to insure complete combustion of the material and the gaseous product therefrom in the kiln whereby the combustion gases may be used effectively to dry the material without quenching the combustion gases prematurely.

The present invention provides a novel unit of simple mechanical construction which is economical in maintenance and operation, and is fully effective in operation and use.

All of the objects of the present invention and the various features and details of the construction and operation thereof are more fully set forth hereinafter with reference to the accompanying drawing in which:

Fig. 1 is a plan view of an installation embodying an incinerator made in accordance with the present invention;

Fig. 2 is a side elevational view at a greater scale of the installation shown in Fig. 1;

Figs. 3a and 3b, when placed end to end, form an enlarged vertical section through the incinerator unit of the present invention;

Fig. 4 is an enlarged transverse section taken on the line 4-4 of Fig. 3a;

Figs. 5 and 6 are enlarged transverse sections taken on the lines 5-5 and 66 respectively of Fig. 3b; and

Fig. 7 is a fragmentary view in elevation of the draft regulator shown at the right hand end of Fig. 3b.

Referring now to Figs. 1 and 2 which show a typical installation embodying an incinerator unit made in accordance with the present invention, the incinerator unit 10 is provided with a burner 11 at one end and a material infeed screw 12 at the other end which feeds material 2 into the unit 10 from a hopper 13. The material is dried and burned in the unit 10 and the combustion gases are conducted away by an exhaust flue 15 connected by a stack 16 to a dust separator or the like, in the present embodiment consisting of a cyclone 17 from which the cleaned combustion gases are exhausted by a blower 18 through a chimney 19. In some installations, the dust separator may be omitted, and the stack may provide sufiicient draft to eliminate the necessity for a blower.

The incinerator unit comprises an elongated cylinder 20 having a material feed section 21, a drying section 22, a transfer section 23, and a burning or incinerating section 24. The burning section 24 is open into a burner box 25 which mounts the burner assembly 11, draft regulators 26, 26,, and a clean-out door 27 (see Fig. 2) The cylinder 20 is rotatable in the burner box 25 and is sealed against escape of gas by a conventional gas seal indicated at 28. The opposite end of the cylinder 20 opens into the exhaust flue 15 through an opening 30 and is sealed therein by a gas seal as indicated at 29. Thus, the combustion gases flow countercurrent to the material feed in the incinerator unit and serve as a drying medium for the wet material.

The cylinder 20 is insulated at the burner end of the unit as indicated at 31 and is a simple shell at the material feed end, although the insulation, if desired, may be extended the full length of the cylinder. The cylinder is rotated by a friction drive, as indicated at 32 which may be driven by a variable speed motor 33. An additionary rotary support for the cylinder is provided at 34.

Means is provided in the material infeed section 21 of the cylinder 20 to advance the material introduced by the feed screw 12 into the dryer section 22 of the cylinder. To this end, the interior periphery of the cylinder is provided with inwardly-projecting radial vanes 36 which are helical in form and serve to advance the wet material from a point underlying the open end of the feed screw 12 into the drying section at a fairly rapid rate, so that the level or the material in the infeed section 21 is maintained low, for example, as indicated by the broken line at 37.

In the present embodiment of the invention, the drying section 22 of the cylinder 20 retains the material and tumbles the same for a predetermined period. To this end, the interior periphery of the cylinder 29 in the drying section 22 is provided with axially-extending inwardly-proj cting radial vanes 38. The vanes 38 carry the material upwardly and tumble it in the drying section to insure effective drying of the material. The axially extending vanes 38 permit the material to accumulate in the drying section 22, for example as indicated by the broken lines at 39.

In accordance with the invention, the dried material is advanced rapidly through the transfer section 23 of the cylinder 20 to retard accumulation of the material in the 7 transfer section and eliminate the premature quenching of the burning combustion gases by partially dried material. To this end, the interior surface of the cylinder in the transfer section 23 isprovided with inwardly-projecting radial vanes of helical form which rapidly advance the material from the drying section 22 to the incinerating section 24. The vanes 40 are mounted on a framework 41 secured to the cylinder 20 in the drying section, as indicated at 42 and secured at the other end to the cylinder 20 in the burner box 25 by an expansion joint indicated at 43. The helical vanes 40 maintain the material level at a minimum, for example, as indicated at 44 in Fig. 3b.

In accordance with the invention, the material is retained in the incinerating section 24 until combustion is complete. To this end, the frame 41 mounts a pluv rality of inwardly-projecting radial vanes extending axially of the cylinder in the incinerating section. The vanes 45 -3.181111'116121; their forward end as indicated at 47 to force the material backward away from the burner box 25 until the material is consumed. A certain amount of incombustible material will flow into the burner box where it may be removed through the clean-out door 27 (see Fig. 2). Thusthe material, by reason of the axially extending vanes 46, is tumbled continuously in the incenerating section 24. Alternate vanes 46, if desired, may be provided with lifters 48 to assist the tumbling action and insure cascading of the material through the flame in the incinerating. section 24.

As shown in Fig. 3b, the burnerll injects flame into the incinerating section 24 where the material is burned. The burning of the material, in addition to consuming the solid matter, also draws off the volatile constituents of the material which, in themselves, may be combustible. The volatile constituents flow into the transfer section under the draft of the flame, and by reason of the construction, the volatiles will be subject to complete combustion in the presence of the hot flue gases. Since the level of the material in the transfer section 23 is maintained at a minimum, the material does not have an opportunity to quench the combustible volatiles and the combustion of the material will be complete. Of course, when burning certain materials, the solids may not be completely combusted and the residue passes out of the unit as soot or the like, or is collected in the bottom of the burner box where it is removed through the cleanout door 27. However, the volatiles which include odif erous compounds are completely combusted and/or destroyed.

. The burner unit operates to initiate combustion of the material in the incinerating sect-ion and where the heat of combustion of the material is suflicient to support combustion, the burner may be turned off. On the other hand, where the water content of the material is extremely high and/or the heating value is low, the burner may operate continuously to support combustion.

In certain installations, for example, when the material has low moisture content and/or high volatile content, the spiral of the transfer section 23 may be extended into the drying section, or the drying section may be eliminated entirely. The length of the sections may be varied within wide limits to accommodate the character of the material being incinerated. j

In a particular installation, where coffee grounds'containing approximately 60% water are incinerated, it has been found that an eighteen-foot cylinder having a three- With the unit of the present invention having these characteristics, it is possible to successfully incinerate 500 pounds per hour of wet coffee grounds.

While a particular embodiment has been illustrated and certain modifications suggested, it is not intended to limit the invention to such disclosure, but other changes and modifications may be made therein and thereto within the scope of the following claims:

We claim: I

1. Apparatus for drying and incinerating wet solid material comprising an elongated cylindrical shell dis posed with its axis horizontal, means to feed wet solid material into one end of said shell, means to slowly advance and cascade and at least partially dry the material at said one end defining a drying section in the shell adjacent said one end, burner means at the other end of the shell to inject flame into the interior of said shell, means to rotate said shell about its axis, axial lifter vanes mounted'on the interior of said shell at said other end 4 projecting radially inward and terminating in oifset portions to cause the material to cascade through the flame injected by said burner for incineration of the solid material, said axial vanes defining an incinerating section in said shell adjacent said other .end;- means to retard passage of the solid material beyond said other end of the shell, said incinerating section of said shell being spaced axially from said drying section a distance to define therebetween a central transfer section in said shell, said transfer section having an axial length suflicient to afiord complete combustion before entry into said drying section of the partially combusted gaseous and gas-borne particulate material'passing from said incinerating section through said transfer section; flue. means at said one end of said shell to receive the completely combusted gaseous and gas-borne particulate material passing from said drying section, and helical vane means mounted about the interior periphery of said shell in at least said transfer sect-ion thereof, projecting radially inward and being at a steep angle relative to said lifter vanes to rapidly transfer the partially dried material without substantial cascading from the drying section to the incinerating section upon rotation of said shell.

-2. Apparatus according to claim-l wherein said cylinder is imperforate and of uniform cross section throughout its length. a

,.,3. Apparatus according to claim 1 wherein said drying means comprises inwardly-projecting radial vanes extending axially of said cylinder intermediate said wet material feed means and said helical vane means to tumble the wet material in the presence of the combustion gases from the burning material, to at least partially dry the material prior to transferring it to the said other end of the shell.

I .4. A dryer-incinerator unit comprising an elongated imperforate open-ended cylinder of uniform internal diameter mounted with its axis horizontal, means to rotate said cylinder about its horizontal axis, a flue connected to one end of said cylinder, a gas seal between said cylinder and said flue, a solid material in-feed screw conveyor mounted in said due and projecting into said one end of the cylinder, a burner box connected to the other end of .said cylinder, a gas seal between said cylinder and said burner box, a burner unit mounted in said burner box to project flame coaxially into said cylinder at said other end, draft regulating means in said burner "box, and inwardly-projecting radial materialengaging vane means mounted on the interior periphery of said cylinder to transfer'the solid material from said one end to the other end of the cylinder and to tumble said material in said cylinder adjacent said burner box, said vane means defining a material feed'section, a drying section, a transfer section, and an incineratingsection in sequence from the one end to the other end of the cylinder, said transfer section having a length sulficient to enable complete combustion of the gaseous and gas-borne particulate material evolved from said solid material in the incinerating section of the cylinder and passing countercurrent to the travel of the solid material in said transfer section prior to its passage into said drying section, the vane means in said drying section being substantially axial to eifect a slow advance of the material into one end of said shell, means to slowly ad Vance and dry the solid material in said shell defining a drying section at said one end, means at the other end of the shell defining an incinerating section and comprising means including axial litter vanes to cascade and effect burning of said solid material and form a burning gaseous product in the interior of said shell, said drying and incinerating sections being spaced apart to define therebetween a transfer section affording complete combustion of the gaseous and gas-borne particulate material emanating from said incinerating section prior to its passage into said drying section, means to rotate said shell, and helical vane means mounted about the interior periphery of said shell in said transfer section thereof at a relatively steep angle to rapidly transfer the material from said drying section to said incinerating section without substantial cascading upon rotation of said shell.

References Cited in the file of this patent UNITED STATES PATENTS 1,703,635 Ranson Feb. 26, 1929 1,929,880 Darrah Oct. 10, 1933 2,043,459 Windecker June 9, 1936 2,243,192 Olark May 27, 1941 FOREIGN PATENTS 1,037,659 France May 6, 1953 

